Question

describe the common characteristics and design of a case-control study. discuss the three importance features when it comes to selecting cases and control, and identify a situation when one of these might be violated. discuss the limitations of using questionaires for determining exposure status and provide examples of alternative stratergies for collecting this information in a case control study

Answer 1

A) common characteristics & design of case - control study:

1) it is quantitative type of study

2) The data is collected retrospectively that is from past to future or exposure to effect.

3) The researcher does not follow patients into future & often requires less time.

B) Features when selecting case - control.:

1. The comparison group (controls) should be representative of the source of population that produced the cases.

If the comparison group ( controls) not the representative of the population their will be recall bias. That means the controls must be of same properties that of population.

2. The controls must be sampled in a way that is independent of exposure; meaning that their selection should not be more or less if they have exposure of interest.

3. The samples should be selected by appropriate sampling techniques that is survivor sampling & case-base sampling.

C) Methods of data collection :

Data for case-control study is typically collected by:

INTERVIEWING & SURVEYING the cases & controls.  

Both cases & controls are asked the same series of questions regarding their medical history and exposure to the factors that are responsible for developing the disease.

Limitations of using questionnaire method of data collection are :

1. Hard to convey emotions and feelings.

2. Respondents may have hidden agenda.

3. Analysis may be difficult for some questions.